JP2016538982A - Flexible catheter with drive shaft - Google Patents

Abstract

The present invention relates to a flexible catheter (1) comprising a drive shaft (2), a sleeve (6) surrounding the drive shaft (2), and a sheath (7) surrounding the sleeve (6) and the drive shaft (2). ), The drive shaft, sleeve (6), and sheath (7) are flexible, and the drive shaft (2) drives the drive shaft (2) at the proximal end of the drive shaft (2). It has a coupling element (5) for connection to a motor (18), the drive shaft (2) is composed of an alloy at least in certain areas, the alloy being at least 10% by weight Each of chromium, nickel, and cobalt. The invention further relates to a blood pump arrangement having this type of catheter.

Description

  The present invention relates to a flexible catheter comprising a flexible drive shaft according to the preamble of the main claim and to a blood pump arrangement comprising such a catheter.

  Such catheters are typically used in the human or animal body to create or transmit torque or rotational movement. The drive shaft runs axially along the longitudinal extent of the catheter between the proximal end of the catheter and the distal end of the catheter. Typically, the proximal end of the drive shaft is connected to the drive motor outside the body to produce torque or rotational movement and transmit it onto the drive shaft. Yes. A rotating or functional element designed according to the respective application is connected to the drive shaft in a rotationally fixed manner at the distal end of the drive shaft. With respect to the functional element, it can be, for example, the case of a milling cutter, a rotor ablator or a pump rotor for delivering blood.

  For many applications, over the duration of each application, along the desired path through the body to position the distal end of the catheter at a desired location in the body, eg, in the heart ventricle. For example, it is necessary to guide the catheter along or in the blood vessel. Apart from the softness and flexibility required for this, in general, still further criteria have to be met. For example, some applications require that rotational movement be created or transmitted by the drive shaft at very high rotational speeds, for example, the required rotational speed is, for example, the case of delivering blood Can exceed 10,000 revolutions per minute, exceed 20,000 revolutions per minute, or even exceed 30,000 revolutions per minute, such as those already described in. Moreover, a rotational movement must be created over a longer period of time and thus over hours, days or weeks, as can be the case when delivering (pumping) blood. In the case, particularly high demands on the drive shaft are directed towards the load bearing of mechanical and chemical catheters. The material fatigue and damage process for the catheter drive shaft and other components should only proceed as slowly as possible, and should proceed as predictably and controllably as possible. Rupture and breakage of the drive shaft during operation should be ruled out with as much certainty as possible in important applications such as when delivering blood. This is undesirable if the flexible drive shaft is too stiff and is operated in a sheath that wears the shaft.

  On the other hand, if a shaft failure occurs in spite of this, the end of the shaft, which is typically unfolded and opened with the maximum possible certainty, passes through the sheath of a catheter, usually made of plastic. It must be ensured that it does not move at high speed. The end of the shaft will rotate freely in the blood vessel in such a case.

European Patent Application No. 2399639

The Sternotomy Hemopump. A second generation intraventional ventricular assist device "Wampler RK et al., ASAIO J. et al. 1993 Jul-sep; 39 (3): M218-23

  The object of the present invention is therefore a flexible catheter with a flexible drive shaft, which is as reliable as possible and capable of permanent operation at high speed. It is to propose a flexible catheter that is as suitable as possible. Moreover, blood pump arrangements have been proposed, which are likewise as reliable as possible and suitable for permanent operation at high speed as much as possible.

  This object is achieved by the catheter according to the main claim and by the catheter and blood pump arrangement according to the auxiliary claim. Preferred embodiments and further developments will be deduced from the dependent claims.

  As described in detail below, this patent application discloses several embodiments, each of which is part of a coherent invention. On the other hand, each of the aspects already represents an autonomous invention in itself. Thus, aspects can be implemented independently of one another (and in each case taken by itself represents a special further development of the generic catheter with the preamble of the main claim). In addition, it can be combined indefinitely with each other to synergistically improve a generic catheter or blood pump arrangement comprising a generic catheter. Thus, for example, a generic catheter can be designed according to one of these aspects and at the same time can be designed according to one (or more) further aspects. This catheter is then a particularly advantageous embodiment of the catheter according to the first mentioned aspect. Thus, each of the aspects also allows further development of each other aspect.

  The first of these aspects relates to the material or material properties of the drive shaft, the second aspect relates to the geometric design of the drive shaft, the third aspect relates to the sleeve design, the fourth An aspect relates to the connection between the drive shaft and the drive motor, a fifth aspect relates to the mounting of the drive shaft, and a sixth aspect relates to a lubricant for the drive shaft. Each of these aspects contributes to improved load bearing and reliability of the catheter or blood pump arrangement.

  Thus, the generic flexible catheter comprises a drive shaft, a sleeve surrounding the drive shaft, and a sheath surrounding the drive shaft and sleeve, where the drive shaft, sleeve, and sheath are flexible. The drive shaft includes a coupling element or coupling head at the proximal end of the drive shaft for connection of the drive shaft to the drive motor.

  Typically, the total length (in the axial direction) of the catheter is between 50 cm and 200 cm, and generally the total length is in the region between 80 cm and 150 cm. Typically, the total length (in the axial direction) of the drive shaft, sleeve and sheath is also in one of these regions in each case as well. Thus, the flexibility or flexibility of the catheter, in particular the flexibility or flexibility of the drive shaft, sleeve and sheath, is a radius of curvature in the region between 20 mm and 40 mm, preferably between 25 mm and 35 mm. It should be sufficient to be able to bend the catheter elastically with a radius of curvature in the region, in particular about 30 mm. With such curvature, among other things, drive shafts and sleeves that rotate at operating speeds should only be elastically deformed, if possible, and therefore, if possible, permanent drive shafts or sleeves. No (plastic) deformation or change should occur. In particular, such an elastic curve with the stated radius of curvature should also be possible by an approximately U-shaped curve of the catheter of about 180 °, so that the catheter can for example be Curved continuously along the axial section of the catheter having a length of about 80 mm to 150 mm (depending on the radius of curvature), typically 100 mm to 120 mm. Such bending of the catheter occurs, for example, when the catheter runs through the aortic arch and into the left ventricle. Moreover, the regular changes in the radius of curvature described typically occur due to regular cardiac action, and the position of the curvature relative to the catheter can also vary regularly.

  In many cases, it is not necessary for the catheter to have such flexibility along its entire axial extent. It may already be sufficient for this to be given in a particular axial section (or several axial sections). In many cases, for example, when the distal end of the catheter must be placed in the ventricle, at least the distal end piece or the distal partial piece of the catheter, as in the case of delivering blood , Has such flexibility. This distal end piece or partial piece can have an axial length, for example in one of the above-mentioned length regions.

  As described in more detail further below, and the flexibility and flexibility of the catheter or drive shaft is not too great in some cases, especially in their axial sections of the drive shaft. It is possible that the drive shaft runs distally or proximally outside the sleeve or out of the sleeve, and local reinforcement of the drive shaft to a certain degree is in these sections May be advantageous in at least one of or may be required depending on the requirements of the respective application. Vibration minimization can advantageously be achieved by such reinforcement, and by such means the risk of hemolysis may also be reduced.

  According to a first aspect of the present invention, the catheter drive shaft may be composed entirely or at least locally of an alloy containing at least 10% by weight chromium, nickel and cobalt in each case. The alloy preferably contains at least 30 wt% nickel, but preferably no more than 40 wt% nickel. The alloy preferably contains at least 30 wt% cobalt, but preferably no more than 40 wt% cobalt. The alloy preferably contains at least 15 wt% chromium, but preferably no more than 25 wt% chromium. The alloy also preferably contains molybdenum, preferably at least 5% by weight, but preferably no more than 15% by weight molybdenum.

  The alloy can include, for example, about 35 wt% nickel, about 35 wt% cobalt, about 20 wt% chromium, and about 10 wt% molybdenum as the alloy composition. These alloy compositions of the alloys can be larger or smaller, up to 3% by weight in each case, or larger or smaller, up to 2% by weight in each case. is there. The alloy composition of these elements can correspond to the alloy composition of these elements in alloy MP35N®, or the alloy composition of these elements in alloy 35NLT®. Can be accommodated, or in each case up to 2% by weight, higher or lower, otherwise, or in each case up to 1% by weight, higher or lower This is different. Moreover, the alloy can contain additional alloying elements. These can be selected and weighted according to alloy element of alloy MP35N® or alloy element of alloy 35NLT®.

  Preferably with respect to the alloy, it is the case of MP35N® or 35NLT® or in a corresponding (or the same) manner, ie by a corresponding (or the same) method step and , MP35N® or 35NLT®, or the same (or the same) process parameters. For example, it can be expected that a drive shaft or an alloy of the entire drive shaft will be work hardened, manufactured or formed by applying (high) cold forming or work hardening. The degree of work hardening of the material of the drive shaft and / or sleeve is, for example, between 35% and 70% and / or between 40% and 60%. The tensile strength of the material in the region between 1900 MPa and 2200 MPa can result from this.

  The relationship between yield point, tensile strength, elongation at break, and degree of work hardening using the example of material 35NLT is illustrated by way of example in FIGS. 16 and 17 (based on the details of manufacturer Fort Wayne Metals). Yes. This example shows that different heat treatment conditions and work hardening levels of materials can generally lead to very different material properties. In many cases, these have simply been found to be inappropriate for flexible drive shafts with the benefit of hindsight.

  For example, high work hardening is not unimportant. The reason is that this may lead to a reduction in the maximum elongation at break and toughness of the material. The reverse bending strength of the drive shaft and the achievable bending radius of the shaft can be adversely affected thereby. On the other hand, low work hardening is accompanied by relatively low material hardness and tensile strength. Hardness that is too low has a direct impact on the wear behavior of the shaft, and hence its fatigue strength, and can result in increased wear and wear during operation, for example. . This is particularly important in the case of sliding / friction pairing, as is typical for flexible shafts. Reduced tensile strength results in low repeated bending strength.

  The optimization of a stable and durable flexible drive shaft is highly complex. The reason for this is that different drive shaft optimization goals involve divergent material properties so that no standardized and meaningfully applicable optimization method or explicit parameter window results in this regard. It is.

However, the surprisingly, completely or at least locally, a tensile strength in the region between 2400 N / mm ² from 1800 N / mm ^2, preferably, 2034N / mm ² from 2241N / mm ² (hence, from 295KSI It has been found that a drive shaft made of a material having a tensile strength of 325 KSI) leads to good results. In particular, with respect to the material, it may comprise one case of the alloys described herein, and thus in each case at least 10% by weight chromium, nickel, and cobalt. However, apart from these alloys, for example metallic and non-metallic materials, in particular plastics and composite materials, other materials are also contemplated for the drive shaft.

  Drive shafts composed entirely of at least locally, such alloys or such materials, are also suitable for applications in very high speeds and long permanent movements, It is also possible to maintain the initially stated speed range over a longer period of time. Torque is transmitted by such a high rotational speed through the drive shaft, but is typically relatively low, especially when delivering blood, and the torque for driving the inflated pump rotor is more Due to the large diameter, it is typically larger. However, the application of alloy MP35N® or alloy 35NLT® is known for different medical devices such as stylets, for example due to their load bearing and their corrosion resistance Their suitability for flexible drive shafts is surprising even if they may be. In particular, in light of the fact that full cyclic loads in excess of 500 000 000, and in extreme cases in excess of 1 000 000 000, can occur by application as a blood pump, among others, Due to the special requirements described, at high speeds, long motion durations and large curvatures.

  Alloys having a relatively high iron or titanium content have heretofore been applied for drive shafts, in particular for blood pumps, in order to achieve high load bearing. However, as found within the framework of the present invention, it is possible to do as much as possible of high content of iron and titanium, or in practice, to do as little as possible Should be capable of permanent operation at high rotational speeds. The weight composition of iron and titanium is more preferably selected relatively low, for example in each case less than 2% or even less than 1% by weight. In principle, it is possible to dispense with iron and titanium completely as alloy composition, which corresponds to a weight composition of less than 0.1% in each case.

  According to a first aspect, the driveshaft is an alloy having a weight composition of iron of less than 2%, or preferably less than 1%, or particularly preferably less than 0.1%, completely or at least locally Can be constructed. According to a first aspect, the drive shaft has a weight composition of titanium of less than 2%, or preferably less than 1%, or particularly preferably less than 0.1%, completely or at least locally. It can be composed of an alloy.

  The drive shaft, sleeve, sheath and / or possibly present bearing elements are made of biocompatible material as much as possible, or at least the outer surface of each component is made of biocompatible material Has been.

  According to a second aspect of the present invention, the drive shaft can include a cavity extending axially through the drive shaft. Thus, with respect to the drive shaft, it can be a hollow shaft case. The cavity can extend into the drive shaft along a complete longitudinal extension range of the drive shaft. At the same time, the high flexibility of the drive shaft with a relatively high torsional stiffness can be realized by such a cavity. Flexibility may be further increased if the drive shaft includes multiple or multiple coaxial windings that run helically around the cavity of the drive shaft. Moreover, torsional and bending stresses can be converted into axial tensile or compressive stresses by means of windings, and by such means the drive shaft load can be reduced. Moreover, it is possible that the windings of the drive shaft are arranged in two or more coaxial layers of the drive shaft. The windings in the different coaxial layers then preferably have opposite winding directions. Then, the tensile and compressive stresses between the layers and those caused by torsional stresses can be offset in this way, either completely or partially. Also, overall, the bending stress in the drive shaft can therefore be reduced.

  With respect to drive shaft windings, it is typically the case of a wound wire or several corresponding wound wire windings. The drive shaft contains exactly one or several such wires in each layer, for example 1 to 8 wires, preferably 4 to 6 wires, particularly preferably 5 wires It is possible. The one or more wires are preferably composed of the alloys described above. The wire or wires typically have a diameter in each case in the range of about 0.09 mm to about 0.21 mm, preferably in the range of about 0.135 mm to about 0.165 mm. ing. The outer diameter of the drive shaft is typically in the range of about 0.53 mm to about 1.32 mm, preferably in the range of about 0.79 mm to about 0.97 mm. A drive shaft outer diameter of less than 1 mm is particularly suitable. The inner diameter of the drive shaft is typically in the range of about 0.17 mm to about 0.39 mm, preferably in the range of 0.25 mm to about 0.31 mm. In the case of two concentric layers, the axially adjacent windings of the inner layer are in contact with each other, while the axially adjacent windings of the outer layer are preferably in contact with each other. Not in the range of about 0.018 mm to about 0.042 mm, preferably in the range of about 0.027 mm to about 0.033 mm (assuming drive shaft alignment without curvature in each case) It has a certain axial distance.

  Also, the small outer diameter of the catheter can be realized by the small outer diameter of the drive shaft, and by such means, a reduction in tissue trauma at the puncture site can be realized. Further benefits that can be realized by the lower outer diameter of the drive shaft are lower friction and wear problems due to reduced drive shaft ambient speed, lower vibration problems due to lower drive shaft mass, and Reduced disturbance / interference of the motor current signal due to the resulting vibration and, for example, calcifications that may be present in the blood vessel are disconnected from the vessel wall and possibly circulated Reduction of the risk of potentially fatal consequences.

  Surprisingly, therefore, for example, to drive an inflatable pump rotor that is in an inflated condition, a sufficiently high torque transmission is less than 1 mm as described herein over a longer period of time. It has been found that even a low outer diameter of the drive shaft is possible. Thereby, it has been found that, inter alia, the special range of wire diameters, and those specified above, are particularly advantageous in the case of shafts constructed from such wires, It has been found that the optimum region for the diameter of the individual wires relates to the outer diameter of the drive shaft in a non-obvious manner.

  In addition, it is possible to expect that the drive shaft windings are manufactured or formed by (high) cold forming or work hardening to improve the elasticity and durability of the drive shaft. is there.

  The cavities are filled with reinforcing material, either completely or in the axial section of the drive shaft, setting the rigidity and stability of the drive shaft in each axial section (in some cases It is possible to increase it (locally). As already explained in the context of the first aspect of the present invention, apart from the sufficient flexibility of the drive shaft, the sufficient rigidity of the drive shaft can also be reduced, especially at high speeds and longer operating durations. Required for reliable operation of, for example, axial sections of the drive shaft that run distally or proximally outside the sleeve, respectively (the distal end piece and the proximal end of the drive shaft, respectively) In the piece), the drive shaft can be rotated stably. The first and second aspects of the invention thus complement each other synergistically. Thus, in a preferred embodiment, it is anticipated that the distal end piece of the drive shaft and / or the proximal end or end piece of the drive shaft will be reinforced. The reinforced distal or proximal end or end piece preferably has a length between 10 mm and 60 mm, particularly preferably between 20 mm and 50 mm. The drive shaft is preferably reinforced in these areas, so that the bearing element (in addition to or instead of the sleeve, i.e. instead of the sleeve) is axial and / or of the drive shaft. Arranged for radial mounting. Moreover, it may be advantageous to reinforce the drive shaft in that region, the drive shaft entering or exiting proximally to the sleeve and consequently not being guided in the sleeve. Moreover, it may be advantageous to reinforce the drive shaft in that region, and the drive shaft enters or exits the sleeve distally. In fact, in these transition regions, other loads such as, for example, drive shaft bending loads, or vibration loads may be reduced by drive shaft reinforcement.

  Materials characterized by high rigidity on the one hand and at the same time relatively high elastic deformability on the other hand are suitable as reinforcing materials for reinforcing the drive shaft. In particular, the reinforcing material or reinforcing material should withstand all bending that the catheter or the pump head of the catheter undergoes during implantation and operation. For example, non-rusting austenitic steel is considered as a reinforcing material, for example steel according to material number DIN 1.4310.

  Also, alternatively or in addition to the described reinforcing materials, suitable reinforcement is (axially and / or radially) adjacent (axially or radially) of the winding of the (helical) drive shaft. (Radial) welding or soldering. Moreover, certain (and sufficient under certain circumstances) reinforcement of the drive shaft can be realized by a distal functional module, which is typically Is fastened on the outer periphery of the drive shaft in a rotatably fixed manner, for example a pump rotor.

  According to a third aspect of the invention, the sleeve can be designed as a bearing coil comprising a plurality of windings. The windings of the bearing coil run axially around the drive shaft in a spiral manner. The bearing coil can be, for example, a wound flat tape. The flat tape preferably has a width (measured in the axial direction), the width being at least 3 times, preferably 6 times greater than the thickness (measured in the radial direction). . Typically, the winding width is in the range of about 0.36 mm to about 0.84 mm, preferably in the range of about 0.54 mm to about 0.66 mm. The winding thickness is typically in the range of about 0.06 to about 0.14 mm, and preferably in the range of about 0.09 mm to about 0.11 mm. The inner diameter of the sleeve is typically in the region between about 0.6 mm and about 1.4 mm, preferably in the range of about 0.9 mm to about 1.1 mm. The outer diameter of the sleeve is typically in the range of about 0.72 mm to about 1.68 mm, preferably in the range of about 1.08 mm to about 1.32 mm. The pitch of the bearing coil is preferably in the range of about 0.43 to about 0.98, preferably in the range of about 0.63 to 0.77, and the inner diameter of the sleeve is outside the flexible drive shaft. It corresponds to the diameter, and in particular is larger than the outer diameter of the drive shaft.

  In the case where the bearing coil is designed as a flat tape on which it is wound, it is possible with respect to the (axial) tilt of the winding with respect to the longitudinal axis of the bearing coil (under straight conditions without bending of the bearing coil) As low as possible manufacturing tolerances. The inclination is preferably less than 10 °, particularly preferably less than 5 °. Therefore, the inner surface of the sleeve or the inner surface of the bearing coil winding preferably forms a cylindrical shaped partial surface instead of a conical shaped partial surface (tilt). The inclination of the winding relative to the longitudinal axis leads to a reduction in the available bearing surface and a greater pressure load on the drive shaft. The outer edge of the flat tape is preferably as rounded as possible so as to avoid pressure peaks on the drive shaft as much as possible. The radius of curvature of the edge is preferably 0.04 mm or more.

  The sleeve can be composed entirely or at least locally of an alloy. Also, therefore, descriptions of drive shaft alloys can be given to sleeve alloys. In particular, the sleeve may be composed entirely or at least locally of the same material, for example the same alloy as the drive shaft.

  In clinical tests, very good results can be achieved in fatigue tests by using the same material for the drive shaft and sleeve under different pulsating loads and with bending radii significantly below 50 mm It was. This is surprising in many aspects. For example, specifically, for patient safety reasons, it is recommended to design a flexible shaft of a material that is relatively hard and wear resistant compared to the drive shaft, for example, usually in a damaged area In the case of shaft breakage that leads to splicing of the shaft at It is designed to prevent rotation. Moreover, in classical engineering, the use of materials equal to sliding or friction partners is usually suppressed. The reason is that in this case so-called “eating” or erosion of the workpiece can occur, because the individual molecules of the two sliding / friction partners connect to each other, and then It stems from the fact that it can be pulled off from the molecular interconnections of other parts. The fact that it is very difficult or impossible to predict which of the two parts will wear appears thereby to be particularly important. Thus, it has been proposed here to use the same material for the rapidly rotating flexible shaft and the bearing coil positioned around it, which is surprising to those skilled in the art. .

  The fourth aspect of the invention relates to the design of the drive shaft proximal coupling element or coupling head, which surprisingly, inter alia, if this aspect is combined with one of the other aspects, The reliability of the catheter and its suitability for permanent application can likewise be significantly improved. The basic idea of the fourth aspect is that the coupling element of the drive shaft (the coupling element of the drive shaft itself is as rigid as possible, fixed in a rotatable, retractable and compressible manner. In the drive shaft) and the coupling element of the drive motor (the coupling element of the drive motor corresponds to this, but is rotatably fixed), but If a compensating movement between the coupling element of the drive shaft and the coupling element of the drive motor is possible in the axial direction, in most cases the axial compressive stress and tension in the drive shaft The stress is that the stress can be significantly reduced. For this purpose, the coupling elements of the drive shaft and the drive motor can include axial sliding surfaces, the axial sliding surfaces corresponding to each other, typically It runs parallel to the (local) rotational axis or longitudinal axis of the coupling element. Thus, the shape of these axial sliding surfaces, or their outer or inner contour, does not change in the axial direction (and thus along the rotational axis or the longitudinal axis). For example, the coupling element of the drive shaft can have a square [end] shape or another profile piece shape, which is defined as a cross-sectional area (perpendicular to the rotational axis or longitudinal axis) Or has an outer contour, which is constant in the axial direction and thus along the longitudinal extent or axis of rotation. Thus, the coupling element of the drive motor can be designed as a receiver designed correspondingly with respect to the square end or profile piece.

  As already mentioned, the catheter can include, for example, a pump rotor for delivering blood at the distal end of the drive shaft, which is fixedly connected to the drive shaft. Depending on the configuration, design, and pitch angle of the pump rotor braiding, the pump rotor can be, for example, a proximal delivery of blood (proximal delivery direction, ie, toward the proximal end of the catheter) or distal delivery ( Can be configured for a distal delivery direction, ie, the direction of the distal end of the catheter. A fifth aspect of the present invention relates to the axial mounting of the pump rotor, with which the catheter thrust bearing is matched to the delivery direction of the pump rotor and the axial bearing force is axial. As a pulling force (and to a lesser extent or not as an axial compression force), mainly or exclusively on the drive shaft. The load on the drive shaft, especially at high speeds, can be surprisingly significantly reduced thereby. Moreover, it has been surprisingly found that the damage to blood due to pumping is reduced by such a design of the blood pump. Thereby, in the case of proximal delivery direction, the thrust bearing is placed proximal to the pump rotor and the axial direction of the distally directed drive shaft (caused by the proximal delivery effect of the pump rotor) Expect to be designed to counteract the displacement of The thrust bearing, in the case of the distal delivery direction, is located distal to the pump rotor and is designed to resist axial displacement of the proximally oriented drive shaft.

  The thrust bearing can include, for example, a first thrust bearing element and a second thrust bearing element, wherein the first thrust bearing element is connected to the drive shaft in a rotationally fixed manner. The second thrust bearing element is fixedly connected to the sleeve or the sheath. The first thrust bearing element and the second thrust bearing element include sliding surfaces (which may also be shown as abutment surfaces or end faces), the sliding surfaces facing each other, preferably Are annular and the sliding surfaces prevent axial displacement of the drive shaft in at least one direction in the case of mutual contact. Thus, the sliding surfaces described overlap one another in the radial direction. The first thrust bearing element can be designed as a radial extension of the drive shaft, but can also be designed as a ring fastened on the drive shaft, for example by crimping. With respect to the second thrust bearing element, it can simultaneously be the case of a radial bearing element, for example the sliding surface facing the drive shaft is preferably designed in a cylindrical shape manner And is arranged coaxially with the rotational axis of the drive shaft.

  Preferably, at least one of the mentioned sliding surfaces or abutment surfaces, preferably at least the sliding surface of the first bearing element of the thrust bearing has profiling and is (lubricated) lubricated Two sliding surfaces with interaction with the agent form a hydrodynamic plain bearing. Furthermore, the lubricant described below is preferably applied as a lubricant. Profiling has the function of creating a lubricant bow or pressure wave between two sliding surfaces that run around the drive shaft during rotational motion. Surprisingly, this design of the sliding surface was able to reduce the increase in wear in this region by more than 50%.

  For example, the profiling of each sliding surface can preferably include 6 to 24 protrusions and / or recesses, preferably the protrusions and / or recesses in each case, It can have a height or depth of about 0.03 mm to about 0.1 mm. Typically, the protrusions and / or recesses can be disposed across the sliding surface in a manner that is uniformly distributed along the circumferential or circumferential direction of the respective sliding surface. The protrusions can be the same, and similarly, the recesses can be the same. The protrusion can be laterally adjacent to the recess and vice versa. In particular, profiling can be designed as a series of alternating protrusions and / or recesses (along the circumferential direction). For example, the protrusions and / or recesses can be designed as ribs and grooves, respectively, which typically start from the inner edge of the sliding surface facing the drive shaft and from the drive shaft. It extends in the direction of the outer edge of the sliding surface that leaves. Typically, the grooves or ribs run strictly from the inner edge to the outer edge exactly and thus have a length corresponding to the radially measured width of each sliding surface. Yes.

  The rib or groove typically has a width (measured in the circumferential direction) in the range of about 0.08 mm to about 0.5 mm. The width of the rib or groove can be constant or can vary in the radial direction. Typically, profiling includes alternating recesses or grooves and protrusions or ribs along the circumferential direction of the sliding surface. Then, when the groove portion has a certain width, the rib portion is typically widened outward in the radial direction. Such embodiments can often be easily manufactured by milling, among other things. On the other hand, when the rib portion has a constant width, the groove portion is typically widened radially outward. However, it is also possible that the width of the rib portion and the groove portion is increased outward in the radial direction. The last embodiment can be manufactured particularly easily by laser cutting. Also, the grooves or ribs can be designed locally helically and thus extend over an arcuate path (eg, a circular path) from the inner edge to the outer edge of the sliding surface.

The catheter can include the bearing elements described above and further bearing elements for radial and / or axial mounting of the drive shaft. Zirconium oxide (ZrO ₂ ; also called zirconium dioxide, zirconia), in particular zirconium oxide stabilized by yttrium, aluminum oxide (AlO _x , typically Al ₂ O ₃ ), ceramic, and context of the first aspect In each case is considered as a material for the bearing element, for example.

  According to a sixth aspect of the invention, the cavity or intermediate gap between the drive shaft and the sleeve is filled with a lubricant, which is biocompatible, preferably physiological But there is. With respect to this lubricant, it can be, for example, the case of distilled water or an aqueous solution, such as a saline solution and / or a glucose solution. The solutions can have a common salt concentration that is physiological, i.e., it is 0.9%. However, it is also possible to envisage isotonic saline solutions or so-called Ringer solutions. On the one hand, since the lubricant does not need to be avoided even if it is not, the structure of the catheter is simplified due to the fact that the lubricant is biocompatible. obtain. Although the materials proposed here are used for drive shafts, sleeves and bearing elements, these components are relatively resistant to corrosion by these (relatively corrosive) lubricants. Being chemically stable, the application of these lubricants is such that the reliability and suitability of the catheter for permanent operation is not practically compromised. The use of a saline solution is particularly advantageous. The reason is that such solutions are generally well tolerated by the patient and have no side effects, especially with the presence of diabetes in the patient.

  The blood pump structure proposed here includes a catheter of the type proposed here and a drive motor for producing rotational movement or torque. A rotationally fixed and preferably axially displaceable connection is between the drive motor or the coupling element of the drive motor already described and the coupling element or coupling head of the drive shaft. Existing. With regard to the latter, reference is made to the description relating thereto and the description in the context of the fourth aspect. Drive motors can be designed to create high rotational speeds, for example, rotational speeds in the region between 10,000 revolutions per minute and 40,000 revolutions per minute. The functional element connected to the distal end piece of the drive shaft in a rotationally fixed manner is designed as a pump rotor. The catheter includes a pump casing at its distal end, in which a pump rotor is disposed. For example, the pump casing has been compressed from an expanded (or compressed) condition (e.g., subject to a (tensile) force acting toward the proximal (or distal) end of the catheter) The pump casing can be designed so that it can be brought to (or inflated) conditions. U.S. Pat. No. 6,057,017 is referenced for details. By using the pump structure, for example, a catheter with its distal end forward is pushed through the femoral artery, through the aortic arch, and into the left ventricle of the heart, leaving the pump casing in the left ventricle. It is possible to predict that The downstream tubing is connected proximal to the pump casing and then typically runs through the aortic valve, which can, for example, direct blood, which is driven by a pump rotor And flows from the pump casing into the aorta. The proximal end of the catheter, and in particular the proximal end of the drive shaft, and the drive motor are located outside the body.

  With these and similar applications, various external force effects and repeated bending loads act on the drive shaft and, in some cases, on the bearing element of the catheter or blood pump component. Changes in body position or posture due to changes in pulsatile pressure or flow of blood associated with the ventricles or blood vessels, such as the left or right ventricle or the aorta, especially due to body position changes or posture changes, Due to the movement, external force effects and repeated bending loads can be transmitted into the catheter, for example by the inner wall of the heart, on which the catheter is supported or even supported on the inner wall of the heart. (E.g. via the so-called pigtail tip). Regardless of this load, statements over longer time periods, for example, over hours, days, or weeks, such as those in the application of the blood pump arrangement described above, etc. Blood can be delivered using the proposed catheter and the proposed blood pump arrangement at a high rotational speed of the pump rotor in the range of speeds being considered.

  For example, as will be inferred from Non-Patent Document 1, laboratory shaft failure is generally simply under pulsatile compressive loads and bend radii below 2 inches (less than 50.8 mm). Can be realistically simulated. This demonstrates the importance of multiple loads on the shaft. Apart from the pump structure proposed here, Applicants have developed a pump with a flexible shaft and one that has been successfully applied under pulsatile loads in the aortic arch for a longer time. Do not know. This is due to the handling of the problem of the flexible shaft, which to date has not been successful. Moreover, so far, particularly in Non-Patent Document 1, the use of a three-layer shaft instead of a two-layer shaft has been viewed as essential to improve the service life of a flexible shaft. The drive shaft proposed here, in contrast, is as long or as conventional as a conventional drive shaft with a two-layer design at small bend radii (less than 50 mm) and pulsating loads. It has much longer durability and load bearing capability than the shaft, and therefore, in embodiments, has a significantly smaller diameter than the conventional drive shaft.

  The outer surface of the drive shaft can surprisingly have a relatively high roughness RZ. The roughness RZ can be, for example, in the range of 0.01 μm to 1 μm, preferably in the range of 0.1 μm to 0.8 μm. The roughness RZ can be, for example, about 0.6 μm. The fact that very good results have been achieved in a durability test with a relatively high roughness of the surface of the drive shaft is quietly surprising. The reason is that, especially when relatively corrosive substances, such as physiological saline or glucose solutions, are used as lubricants as proposed here, they are theoretical. Due to considerations, a surface that is as smooth as possible is usually preferred to minimize wear due to friction, which is common in the industry in terms of its lubricity effect. This is because the design principles that are not close to the lubricant and are usually applicable to classical engineering cannot clearly be given directly in this regard.

  As already explained, a flexible catheter of the type proposed here includes a drive shaft, a sleeve surrounding the drive shaft, and a sheath surrounding the drive shaft and the sleeve, the drive shaft, sleeve, And the sheath is flexible and the drive shaft includes a coupling element at the proximal end of the drive shaft for connecting the drive shaft to the drive motor.

Moreover, the drive shaft can include an outer diameter of less than 1 mm. The drive shaft and / or sleeve has a tensile strength at least locally, preferably between 1800 N / mm ² and 2400 N / mm ² , preferably between 2034 N / mm ² and 2241 N / mm ² Consists of materials. The drive shaft and / or sleeve may be at least locally constructed from a non-metallic material or a metallic material. In the case of metallic materials, it is thereby preferably the case of an alloy as already described further above, which thus contains at least 10% by weight of chromium, nickel and cobalt in each case. contains. This alloy can have the characteristics already described above. The drive shaft and the sleeve can be composed entirely or at least locally of the same material. Moreover, as already explained above, the surface of the drive shaft can have a roughness between 0.01 μm and 1 μm, preferably between 0.1 μm and 0.8 μm. It is. Of course, the catheter can have all of the features and feature combinations, which have been described previously and are described below.

  The described aspects of the present invention will be described in more detail below by way of examples of specific embodiments of catheters of the type proposed here and blood pump arrangements of the type proposed here. It is schematically represented in FIGS. 1 to 16.

1 is a side view of a catheter of the type proposed here. FIG. 2 shows a blood pump arrangement comprising the catheter shown in FIG. 1 in an implanted condition. FIG. 2 is a side view of an axial section of a drive shaft part of the catheter of FIG. 1. FIG. 4 shows a section through the drive shaft represented in FIG. 3 at the location characterized in AA. FIG. 5 shows a side view of a distal end piece of a drive shaft reinforced with a reinforcing material. FIG. 6 is a longitudinal section through the end piece shown in FIG. 5 at the location characterized in AA of FIG. 5. FIG. 2 is a side view of the catheter sleeve shown in FIG. 1. FIG. 8 is a cross-section through a partial region of the sleeve shown in FIG. 7, which is characterized by A in FIG. FIG. 2 is a longitudinal section through the catheter shown in FIG. 1 and in a partial axial section characterized by Y in FIG. 1. FIG. 7 is a view of the distal end piece represented in FIGS. 5 and 6, showing that the pump rotor is fastened in a rotatably fixed manner thereon. FIG. 2 is a longitudinal section through the catheter shown in FIG. 1 and in a partial axial section characterized by Z in FIG. 1. 2 is a longitudinal section through the coupling module of the catheter shown in FIG. FIG. 10 is a perspective view showing an example of a bearing element embodiment of the thrust bearing shown in FIG. 9. FIG. 14 is also a perspective view of an example of a further embodiment of the bearing element shown in FIG. 13. It is a figure which shows the measured value of a yield point, tensile strength, and elongation at break regarding the value from which the work hardening degree regarding material 35NLT (trademark) differs. FIG. 16 is a diagram of measured tensile strength and elongation at break specified in FIG. 15 as a function of the degree of work hardening for the material 35NLT®.

  Repeating one or more features corresponding to each other are characterized by the same reference numerals in the figures.

  A special embodiment of a flexible catheter 1 of the type proposed here is schematically represented in FIG. The catheter 1 includes a flexible drive shaft 2, in which the proximal end piece 3 of the flexible drive shaft 2 will be seen, said end piece protruding from the proximal coupling module 4 (Cantilever), at its proximal end, the drive shaft 2 includes a coupling element 5 for connection of the drive shaft 2 to a drive motor (see FIG. 2). In addition, the catheter 1 includes a flexible sleeve 6 (not shown here, but see FIGS. 7 to 9), which surrounds the drive shaft 2 and is mounted radially thereto. A flexible sheath 7 surrounds the drive shaft 1 and the sleeve 6. Thus, the coupling module 4 and the proximal end piece 3 of the drive shaft 2 are arranged at the proximal end 8 of the catheter 1 while at the distal end 9 of the catheter 1 the catheter 1 is pumped The head 10 includes a pump casing 11, a termination housing 13, and a downstream tubing 12, which is disposed distal to the pump casing 11 and is for the drive shaft 2. The downstream tubing 12 is proximally adjacent to the pump casing 11 (elements running in the downstream tubing 12 are represented by dotted lines in FIG. 1). A support element 14 in the form of a so-called pigtail tip is arranged distally on the end housing 13. In addition, the catheter 1 includes a lock 15. The function of the lock is to compress the pump head 10 radially when the pump head 10 is pulled into the lock 15. This compressed condition pump head 10 can then be guided, for example, through an introductory lock (not shown) and embedded therethrough. The introducer lock can be secured, for example, to a puncture location on or in the patient's body. Thus, the catheter 1 is similarly supported at this location. Reference is made in this context to US Pat.

  This catheter as part of the blood pump assembly 16 is represented in FIG. 2 in a very schematic manner in an implanted condition. Shown is the use or application of the catheter 1 and the blood pump structure 16, with which the drive shaft 2 of the catheter 1 is driven via the coupling element 5 to drive the blood pump structure 1. Connected to the corresponding coupling element 17 of the motor 18 in a rotationally fixed manner (but in an axially displaceable manner; see the description for FIG. 12). The drive motor 18 is designed to produce high rotational speeds in the region between 10,000 revolutions per minute and 40,000 revolutions per minute.

  As shown in FIG. 10, a functional element designed as a pump rotor 20 is connected to the distal end piece 19 of the drive shaft 2 in a rotationally fixed manner. The pump rotor 20 is arranged in the pump casing 11, which in the example of this embodiment can be changed from a condition in which it is radially expanded to a condition in which it is radially compressed. Designed to be For example, this can be achieved with the help of the lock 15 or the introduction lock described above, preferably while the pump casing 11 is subject to a (tensile) force acting towards the proximal end 8 of the catheter, respectively. Can be realized by being at least partly retracted into the lock and thereby being compressed along a radial direction running transverse to the longitudinal direction. Therefore, the pump casing 11 can be changed from the compressed condition to the expanded condition by the reverse force. Reference is also made here to US Pat.

  With the application of the pump arrangement 2 represented in FIG. 2, the catheter 1 with its distal end 9 in front is inserted through the puncture site 21 into the patient's body and into its femoral artery 22. Along this, it is pushed into the left ventricle 24 of the heart 25 through the aortic arch 23. Accordingly, the pump casing 11 is positioned in the left ventricle 24 so that it is supported on the inner wall 26 of the left ventricle 24 by the support element 14, and the downstream tubing 12 is connected to the aortic valve 27. Running through the aorta 28. Accordingly, blood driven by the pump rotor 20 and flowing out of the pump casing is guided into the aorta 28 through the downstream tubing 12. The proximal end 8 of the catheter 1, the proximal end piece 3 of the drive shaft 2, and the drive motor 18 are arranged outside the body.

  In this example embodiment, the total length (in the axial direction) of the catheter and the total length (in the axial direction) of the drive shaft 2 is about 150 cm in each case (corresponding to an implantable length of about 140 cm). The total length (in the axial direction) of the catheter distal end 9 (including the pump head 12 and support element 14) is approximately 13.5 cm to allow this application. Thus, the flexibility or flexibility of the catheter 1, in particular the flexibility or flexibility of the drive shaft 2, sleeve 6, and sheath 7, is quite large and the catheter 1 is implanted as described above. And can be operated. For this purpose, these components must be able to be elastically bent 180 ° at least in the distal end 9 of the catheter, so that, as shown in FIG. Without plastic deformation, a radius of curvature R of the aortic arch 23 of approximately 30 mm typically occurs, in particular the radius of curvature R of the drive shaft 2.

  As shown in FIGS. 4 and 6, the drive shaft 2 is designed as a hollow shaft and includes a cavity 29 extending axially through the drive shaft 2. High flexibility is realized. The cavity 29 extends along the entire length of the drive shaft 2. However, this cavity 29 is completely filled with a reinforcing material 30, a so-called core, at least in the distal end piece 19 approximately 4.5 cm long of the drive shaft (FIGS. 6, 9 and 9). And FIG. 10 and further related description below), where sufficient rigidity and vibration stability of the drive shaft 2 or of the distal end piece 19 of the drive shaft is realized. ing.

The drive shaft 2 includes a number of coaxial windings 31, 32 that run spirally around the cavity 29 of the drive shaft 2 to provide torsional and bending stresses in the axial direction. It converts to tensile stress and compressive stress. The windings 31, 32 are arranged in two coaxial layers 33, 34 (that is, layers) of the drive shaft 2, and the windings 31 are arranged in the common radial direction (same windings) in the inner layer 33. The windings 32 are arranged in a common radial direction in the outer layer 34. The winding 31 of the inner layer 33 has an opposite winding direction compared to the winding of the outer layer 34 so that tensile and compressive stresses can be offset between the layers. . In the example shown, the drive shaft has four wires 35 in the inner layer 33, which are wound coaxially and in a common radial direction around the cavity 29. And the drive shaft has five wires in the outer layer 34, the five wires being wound coaxially and in a common radial direction around the cavity, The axially adjacent windings 31 of each other are in contact with each other, but the axially adjacent windings of the outer layers (in each case, a 5-wire winding packet) 32 are mutually connected. It is not in contact and has an axial distance of approximately 0.03 mm (assuming in each case the alignment of the drive shaft without curvature). The outer diameter d _a of the drive shaft of this example is about 0.88 mm, and the inner diameter d _i is about 0.28 mm. The wire has a circular round cross section with a diameter of about 0.15 mm. In this example, the circumferential direction of the winding 36 of the outer layer 34 is opposite to the specified direction of rotation of the drive shaft 2 for (proximal) delivery of blood.

  Here, this direction of rotation corresponds to a clockwise direction (defined with respect to the direction of viewing the distal end from the proximal end of the drive shaft). In this case, the torque to be transmitted leads to the outer layer trying to shrink and shorten. Since the inner layer 33 has opposite tendencies due to its opposite winding direction, these tendencies often often cancel each other out. Basically, this mutual compensation is the opposite case, specifically when the winding direction of the outer layer corresponds to the direction of rotation and the winding direction of the inner layer is opposite to the direction of rotation of the drive shaft. Can also be realized.

  The wires 35, 36 of the drive shaft 2 are made entirely of an alloy, which has an alloy composition of about 35% by weight nickel, about 35% by weight cobalt, about 20% by weight chromium, and about Contains 10 wt% molybdenum. Also, the alloy composition of the alloys can be greater or lesser up to 3% by weight in each case, or greater or lesser up to 2% by weight in each case. Is possible. With regard to the alloy, in this example it is in particular the case of 35NLT®, but it can be equally easy to be the case of MP35N®. Thus, the weight composition of iron in the wire is less than 1% by weight and the weight composition of titanium is less than 0.1% by weight. Alloy and drive shaft windings 31, 32 are manufactured or formed during high cold forming and work hardening applications. In this example, a non-rusting austenitic steel with material number DIN 1.4310 (X10CrNi18-8) is selected as the reinforcing material 30 to reinforce the drive shaft 2. Alternatively, any other material that meets the requirements further specified above in this context may be selected as the reinforcing material.

A sleeve 6 is represented in FIGS. 7 and 8, which in the example shown is designed as a bearing coil with a number of windings 37, the windings 37 of the bearing coil being in a helical fashion. It runs around the drive shaft 2 in the axial direction. In this example, the bearing coil is provided by a wound flat tape 38. The flat tape 38 has a width B (measured in the axial direction), which is about six times greater than the thickness D (measured in the radial direction). In this example, the width B of the winding 37 is 0.6 mm, and the thickness D of the winding 37 is 0.1 mm. Furthermore, the winding 37 is angled as small as possible with respect to the longitudinal axis L of the bearing coil (under straight conditions with no bearing coil curvature), preferably by less than 5 °, ie The inner surface 39 of the sleeve 6 that is tilted and is formed by the winding 37 is as cylindrical as possible, or forms a partial surface that is as cylindrical as possible. . Moreover, the outer edge 54 of the flat tape preferably is rounded as much as possible, has a curvature radius r _k of about 0.04 mm. The radius of curvature _{r k} edges 54 are preferably exceeds 0.04 mm. Moreover, the inner diameter _{D I} of the sleeve 6 is about 1 mm, the outer diameter _{D A} of the sleeve is approximately 1.2 mm, and has a slope / pitch of about 0.7. In this example, the sleeve 6 or the flat tape 38 is composed of the same alloy as the wires 35, 36 of the drive shaft 2, and is therefore composed here of 35NLT®, but also in this regard. It can also be manufactured from another one of the materials mentioned.

  Also, the drive shaft 2 and the sleeve 6 can be composed of materials other than the alloys described herein. The drive shaft 2 is preferably made from the same material as the sleeve 6. Moreover, the surface of the drive shaft 2 can have a roughness RZ of about 0.6, and surprisingly good wear resistance is achieved by such means. Surprisingly, good wear properties, and thus high operational reliability, can be achieved by these measures that are extremely simple to implement.

  A longitudinal section through the axial section of the catheter 1, indicated by Y in FIG. 1, is schematically represented in FIG. 9. In this section, the catheter 1 includes bearing elements 40, 41, 42 that are proximal to the pump rotor 20 for radial and axial mounting of the drive shaft 2. Has been placed.

  The arrangement and design of these bearing elements 40, 41, 42 is matched to the pump rotor 20 of the catheter 1 shown in FIG. The pump rotor 20 has a braiding 43, which is configured, designed, and pitched angle proximally (in the proximal delivery direction, ie towards the proximal end of the catheter). ) Configured to deliver. The bearing elements 40 and 41 form a thrust bearing 44, which is disposed proximal to the pump rotor 20 (the bearing element 41 is the first thrust bearing element of the thrust bearing 44). The bearing element 40 is the second thrust bearing element of the thrust bearing 44). Due to the design and arrangement of these (thrust) bearing elements 40, 41, the thrust bearing 44 is axially oriented in the distally oriented drive shaft 2 (caused by the effect of the pump rotor 20 delivering proximally). Designed to resist displacement. The axial bearing force acting mainly acts on the drive shaft 2 in this way as a tensile force during the operation of the blood pump component.

  The (first) bearing element 41 is preferably designed in an annular manner and is connected to the drive shaft 2 in a rotationally fixed manner, for example by crimping. In contrast, the (second) bearing element 40 is fixedly connected to the sleeve 6 and the sheath 7 in the same way as the bearing element 42. The bearing elements 40, 41 have annular sliding surfaces 45 and 46, respectively, which are facing each other and are distal when in contact with each other. The axial displacement of the drive shaft 2 in the direction is prevented. The sliding surface 46 of the (first) bearing element 41 has profiling (see FIGS. 13 and 14 and the related description below), by such means two sliding surfaces. The formation of a stable lubricant film between 45 and 46 is encouraged and basically allows the design of the thrust bearing 44 as a hydrodynamic sliding bearing. A lubricant film, i.e., a hydrodynamic bearing in this example, is further formed using the lubricant described below. Moreover, the bearing element 40 is designed as a radial bearing element with a sliding surface facing the drive shaft 2 in each case as well as the bearing element 42 and is designed in a cylindrically shaped manner. The drive shaft 2 is disposed coaxially with the rotational axis.

  Moreover, as will be appreciated in FIG. 9, the drive shaft 2 is reinforced in the axial section by the reinforcing material 30, in which it exits distally from the sleeve 6. In other words, it is mounted by bearing elements 40, 41, 42.

  A longitudinal section through the axial section of the catheter 1, characterized by the reference number Z in FIG. 1, is schematically represented in FIG. 11, which includes, inter alia, a termination housing 13, which includes a termination housing 13. 13 is adjacent to the pump casing 11. The end housing 13 is designed in a tube-like manner, and for the radial mounting of the distal end piece 19 of the drive shaft 2, a distal bearing channel 47 and a bearing arranged therein. Element 47 is included. The cavity 47 is sized, in particular, sufficiently large so as to allow a compensating movement in the axial direction of the drive shaft 2.

  A longitudinal section through the proximal coupling module 4 shown in FIG. 1 is schematically represented in FIG. 12, said coupling module 4 for the proximal end piece 3 of the drive shaft 2 The proximal end piece 3 of the drive shaft 2, which includes a proximal bearing channel 49, runs axially through the bearing channel 49 and projects axially from the proximal coupling module 4. A bearing element 50 for radial stabilization or mounting of the proximal end piece 3 of the drive shaft 2 is arranged in the bearing channel 49. The sleeve 6 extends axially through this bearing element 50 to its proximal end. In this embodiment, the bearing element 50 has a function of stabilizing and supporting the sleeve 6 in the radial direction from the outside. In an alternative embodiment, the sleeve 6 does not run through the bearing element 50 but ends at the distal end of the bearing element 50 (coming from the distal side). In this case, the bearing element 50 is designed as a sliding bearing or a roller bearing, for example. The proximal end piece 3 can be reinforced by the reinforcing material 30 in the axial section, similar to the distal end piece 19, in particular, in which the drive shaft is out of the bearing channel 49. Exits or is mounted by bearing element 50. The bearing elements 40, 41, 42, 48 and 50 are preferably made of zirconium oxide (preferably stabilized by yttrium), aluminum oxide, ceramic or the same material as the wires 35, 36 of the drive shaft 2. It is configured.

  In addition, the coupling housing 4 includes a channel 51 for the supply and discharge of lubricant, the channel 5 being in a fluid-leading manner in the bearing channel 49 and in the sleeve 6 and the drive shaft 2. Connected to an intermediate space between. According to a sixth aspect of the invention, the intermediate space or intermediate gap between the drive shaft and the sleeve is filled with a lubricant, which is biocompatible and preferably also physiological. . The lubricant is biocompatible and in this example is the case of distilled water, but it can also be a physiological saline or glucose solution.

  The coupling element 5 of the drive shaft 2 is designed as rigid as possible and is connected to the proximal end piece 3 of the drive shaft 2 in a fixed manner with respect to rotation, traction and compression. . The coupling element 5 of the drive shaft and the coupling element 17 of the drive motor 18 (designed as a receiver for the coupling element 5 in this example) have axial sliding surfaces 52 and 53 respectively. Including, sliding surfaces 52 and 53 correspond to each other to form a connection that is rotatably fixed but axially displaceable. These sliding surfaces run parallel to the longitudinal axis of the respective coupling element 5 and 17, respectively, and their shape along the longitudinal axis of the respective coupling element 5 and 17 respectively. It has not changed. In this example, with respect to the coupling element 5 of the drive shaft 2, it is a square end case.

  The sheath 7 can be constructed completely or at least locally from plastic, for example polyurethane, in particular carbocein or urethane. The sheath preferably has a metal reinforcement, which can be composed, for example, of a proposed alloy for the drive shaft, and thus, for example, MP35N®.

  13 and 14 show schematic perspective views of examples of embodiments of the first bearing element 41 of the thrust bearing 44 shown in FIG. 9 in each case. The sliding surface 46 of each bearing element 41 includes a profiling 55 so that, by interaction with the lubricant, the two sliding surfaces 45, 46 form a hydrodynamic sliding bearing, By such means, the wear volume of the sliding surfaces 45, 46 or the wear volume of the two bearing elements 40, 41 can be significantly reduced. In the embodiment represented here, the profiling 55 of each sliding surface 46 includes a number of protrusions 56 and recesses 57. In the example shown in FIG. 13, there are exactly 12 protrusions and 12 recesses, and in the example shown in FIG. 14, exactly 8 protrusions and 8 recesses. The protrusion 56 and the recess 57 are in each case the circumferential or circumferential direction of the respective sliding surface 46 (in each case indicated by an arrow characterized by U in the figure) Along the sliding surface 46 and is designed as an alternating sequence of ribs and grooves.

  These ribs and grooves are in each case the outer edge 59 of the respective sliding surface 46 remote from the drive shaft 2 from the inner edge 58 of the respective sliding surface 46 facing the drive shaft 2. It extends to. In the example represented in FIG. 13, the ribs are in each case about 0.06 mm high (this corresponds to the depth of the respective laterally adjacent groove) and about 0 It has an average width of 2 mm (measured in the circumferential direction U). In the example shown in FIG. 13, the protrusions 55 designed as rib portions have a maximum height of about 0.1 mm in each case, and each protrusion has a leading surface 60. And a trailing surface 61, the leading surface 60 in a specified direction of rotation along the circumferential direction U (in the clockwise direction given the direction seen from the distal end 9 of the catheter 1) ) Assuming the rotation of the bearing element 41, it advances with respect to the trailing surface 61.

  The leading surface 60 is inclined or beveled with respect to the longitudinal axis of the bearing element 41 so that the protrusions 56 face upward (ie, the sliding surface 45 opposite the second bearing element 40). In the direction, and thus in the present example in the distal direction), or can be tapered. Thus, essentially any other embodiment example of profiling the bearing element 41 can achieve a more uniform lubricant bow wave, which results in a more stable lubricant film. Can be formed by a leading surface 60 that is beveled, that is, beveled. On its respective upper side 62, each of the protrusions 56 has an average width (measured in the circumferential direction U) of about 0.3 mm, and the width of the protrusions 56 is in the radial direction. It has increased. In this example, the average width of the groove portion 57 (measured in the circumferential direction U) is about 0.1 mm, and the width of the groove portion also increases outward in the radial direction. The embodiment shown in FIGS. 13 and 14 can be manufactured, for example, by a (cutting) laser.

  The dependence of material properties based on details of manufacturer Fort Wayne Metals between yield point, tensile strength, elongation at break, and cold work hardening is shown in FIGS. 16 and 17 using the example of material 35NLT. It is represented. This example shows that different heat treatment conditions and work hardening levels of materials can generally lead to very different material properties.

  For example, if the drive shaft 2 and / or sleeve 6 of the example embodiment shown in FIGS. 1-15 is comprised of 35 NLT, the degree of work hardening of this material is preferably from about 35%. 70%, particularly preferably 50% to 60%, where a tensile strength of about 2000 MPa to 2200 MPa, for example 2068 MPa, is realized, with an elongation at break of 3.5% It will not be below the standard.

  1 catheter, 2 drive shaft, 3 drive shaft proximal end piece, 4 coupling module, 5 drive shaft coupling element, 6 sleeve, 7 sheath, 8 catheter proximal end, 9 catheter distal end 10 pump head 11 pump casing 12 downstream tubing 13 end housing 14 support element 15 lock 16 blood pump assembly 17 drive motor coupling element 18 drive motor 19 distal end of drive shaft Part piece, 20 pump rotor, 21 puncture location, 22 femoral artery, 23 aortic arch, 24 left ventricle, 25 heart, 26 inner wall, 27 aortic valve, 28 aorta, 29 mold 30 Reinforcement material, 31 Drive shaft winding, 32 Drive shaft winding, 33 Drive shaft coaxial layer, 34 Drive shaft coaxial layer, 35 Drive shaft wire, 36 Drive shaft wire, 37 Winding of sleeve, 38 Flat tape, 39 Inner surface of sleeve, 40 Bearing element, 41 Bearing element, 42 Bearing element, 43 Braiding, 44 Thrust bearing, 45 Sliding surface, 46 Sliding surface, 47 Bearing of terminal housing Channel, 48 bearing element, 49 bearing module bearing channel, 50 bearing element, 51 channel for lubricant, 52 sliding surface, 5 Sliding surface 54 edge 55 profiling, 56 protrusion, 57 recess, 58 inner edge, 59 the outer edge 60 leading surface 61 trailing surface.

Claims (29)

A flexible catheter (1) comprising a drive shaft (2), a sleeve (6) surrounding the drive shaft (2), and a sheath (7) surrounding the drive shaft (2) and the sleeve (6) The drive shaft, the sleeve (6), and the sheath (7) are flexible, and the drive shaft (2) is located at the proximal end of the drive shaft (2). In a flexible catheter (1) comprising a coupling element (5) for connecting (2) to a drive motor (18),
The drive shaft (2) is at least locally composed of an alloy containing at least 10% by weight of chromium, nickel and cobalt in each case, a flexible catheter (1 ).   The catheter (1) according to claim 1, wherein the alloy comprises 30 wt% to 40 wt% nickel, 30 wt% to 40 wt% cobalt, and / or 15 wt% to 25 wt%. Catheter (1), characterized in that it contains chromium.   3. The catheter (1) according to claim 1 or 2, wherein the alloy corresponds to material MP35N® or material 35NLT®, at least with respect to the weight composition of nickel, cobalt and chromium. Or a catheter (1), characterized in that in each case it differs from this by less than 3% by weight. Catheter (1) according to any one of claims 1 to 3, wherein the alloy has a tensile strength between 1800 N / mm ² and 2400 N / mm ² , preferably 2034 N / mm ² to 2241 N /. Catheter (1), characterized by having a tensile strength between mm ² .   5. The catheter (1) according to any one of claims 1 to 4, wherein the surface of the drive shaft (2) has a roughness between 0.01 μm and 1 μm, preferably between 0.1 μm and 0. Catheter (1), characterized in that it has a roughness between 8 μm.   6. The catheter (1) according to any one of claims 1 to 5, wherein the outer diameter of the drive shaft ranges from about 0.53 mm to about 1.32 mm, preferably from about 0.79 mm to about Catheter (1), characterized in that it is in the range of 0.97 mm.   The catheter (1) according to any one of the preceding claims, wherein the drive shaft (2) has a cavity (29) extending axially through the drive shaft (2). Catheter (1), characterized in that it comprises.   A catheter (1) according to claim 7, wherein the drive shaft (2) runs in a spiral around the cavity (29) of the drive shaft (2). , 32). A catheter (1).   9. The catheter (1) according to claim 8, wherein the windings (31, 32) are arranged in two or more coaxial layers (33, 34) of the drive shaft (2). The catheter (1), characterized in that the windings (31, 32) in different coaxial layers (33, 34) have opposite winding directions.   10. Catheter (1) according to claim 8 or 9, wherein the winding (31, 32) is formed by at least one wound wire of the drive shaft (2), and the at least one Catheter (1) characterized in that the wire has a diameter in the range of about 0.09 mm to about 0.21 mm, preferably in the range of about 0.135 mm to about 0.165 mm.   11. The catheter (1) according to any one of claims 7 to 10, wherein at least one axial section of the cavity (29) of the drive shaft (2) is arranged in the respective axial direction. Catheter (1), characterized in that it is filled with a reinforcing material (30), preferably stainless austenitic steel, in order to reinforce the drive shaft (2) in the section.   12. The catheter according to any one of the preceding claims, wherein the distal end piece (19) of the drive shaft (2) is reinforced and the reinforced distal end piece (19). ) Preferably has a length of between 10 mm and 60 mm, particularly preferably a length of between 20 mm and 50 mm.   The catheter (1) according to any one of the preceding claims, wherein the catheter (1) comprises a pump rotor (20) at a distal end of the drive shaft (2), The catheter (1), wherein the pump rotor (20) is fixedly connected to the drive shaft (2).   14. The catheter (1) according to claim 13, wherein the pump rotor (20) is designed to produce a flow directed proximally, the catheter (1) being a thrust bearing (44). The thrust bearing (44) is disposed proximal to the pump rotor (20) and resists axial displacement of the drive shaft (2) oriented distally Or the pump rotor (20) is designed to produce a distally directed axial flow and the catheter (1) has a thrust bearing (44) The thrust bearing (44) is disposed distally of the pump rotor (20) and is proximally oriented to the drive shaft Characterized in that it is designed to counteract the axial displacement of the bets (2), the catheter (1).   15. The catheter (1) according to claim 14, wherein the thrust bearing (44) comprises at least one first bearing element (41) and a second bearing element (40), the first bearing. An element (41) is connected to the drive shaft (2) in a rotationally fixed manner, and the second bearing element (40) is in a fixed manner in the sleeve (6) or Connected to the sheath (7), the first bearing element (41) and the second bearing element (40) include sliding surfaces (45, 46), the sliding surfaces (45, 46) are axes of said drive shaft (2) in at least one direction on the premise that they face each other and are in contact with each other Characterized by blocking the displacement of the direction, the catheter (1).   16. The catheter according to claim 15, wherein at least the sliding surface (46) of the first bearing element (41) comprises a profiling (55) for forming a hydrodynamic sliding bearing. A catheter.   17. Catheter according to claim 16, wherein the profiling (55) of the sliding surface (46) comprises several, preferably 6 to 24 protrusions (56) and / or recesses (57). The protrusions (56) and / or recesses (57) preferably have a height and depth of about 0.03 mm to about 0.1 mm, respectively, in each case. A catheter.   18. The catheter according to claim 16 or 17, wherein the protrusion (56) and / or the recess (57) is designed as a rib or groove, the rib or groove being the drive shaft ( Starting from the inner edge (58) of the sliding surface (46) facing 2) in the direction of the outer edge (59) of the sliding surface (46) away from the drive shaft (2) A catheter that is extended and wherein the rib or groove preferably has a width in the range of about 0.08 mm to about 0.5 mm.   19. Catheter according to any one of the preceding claims, wherein the catheter (1) is at least one bearing element for radial and / or axial mounting of the drive shaft (2). (40, 41, 42, 48, 50), preferably at least one of said at least one bearing element (40, 41, 42, 48, 50) is at least locally, zirconium oxide, A catheter, characterized in that it is composed of zirconium oxide, aluminum oxide, ceramic, and / or the alloy specified in claim 1, 2 or 3, in particular stabilized by yttrium.   20. Catheter (1) according to any one of the preceding claims, wherein the sleeve (6) is designed as a bearing coil with a number of windings (37), the windings (37). ) Runs in the axial direction spirally around the drive shaft (2), and the bearing coil is preferably a wound flat tape (38). ).   21. A catheter (1) according to any one of the preceding claims, wherein the sleeve (6) is at least locally the same material as the drive shaft (2) and / or. Catheter (1), characterized in that it is composed of the alloy described in 2 or 3.   A catheter (1) according to any one of the preceding claims, wherein the intermediate space between the drive shaft (2) and the sleeve (6) is a biocompatible lubricant, preferably Catheter (1), characterized in that it is filled with distilled water, saline solution or glucose solution.   23. A catheter according to any one of the preceding claims, wherein the proximal coupling element (5) of the drive shaft (2) comprises an axial sliding surface (52), Directional sliding surface (52) is uniform along the longitudinal axis of the coupling element (5) for connection with the drive motor (18), which is rotatably fixed and axially displaceable A catheter, characterized in that it is designed. A flexible catheter (1) comprising a drive shaft (2), a sleeve (6) surrounding the drive shaft (2), and a sheath (7) surrounding the drive shaft (2) and the sleeve (6) The drive shaft, the sleeve (6), and the sheath (7) are flexible, and the drive shaft (2) is located at the proximal end of the drive shaft (2). In a flexible catheter (1) comprising a coupling element (5) for connecting (2) to a drive motor (18),
Said drive shaft (2) has an outer diameter of less than 1 mm and at least locally a tensile strength between 1800 N / mm ² and 2400 N / mm ² , preferably 2034 N / mm ² to 2241 N Flexible catheter (1), characterized in that it is composed of a material having a tensile strength between / mm ² .   25. Catheter (1) according to claim 24, wherein the surface of the drive shaft (2) has a roughness between 0.01 μm and 1 μm, preferably between 0.1 μm and 0.8 μm. Catheter (1), characterized in that   26. The catheter (1) according to claim 24 or 25, wherein the drive shaft (2) and / or the sleeve (6) are at least locally composed of a metallic material, Catheter (1), preferably an alloy, characterized in that it contains at least 10% by weight of chromium, nickel and cobalt in each case.   27. A catheter (1) according to any one of claims 24 to 26, characterized in that the drive shaft (2) and the sleeve (6) are at least locally composed of the same material. And catheter (1).   A blood pump arrangement (16), characterized in that it comprises a catheter (1) according to any one of claims 1 to 27.   30. Blood pump arrangement (16) according to claim 28, wherein said blood pump arrangement (16) further comprises a drive motor (18), which is rotatably fixed and preferably axially displaceable. Is present between the drive motor (18) and the coupling element (5) of the drive shaft (2).

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